The correct answer is:
an analysis of claims and statements in the text.
Why? Analyzing the claims and statements in an informational text helps readers understand the main arguments and supporting evidence presented by the author. This process directly aids in identifying the central idea, as it requires readers to engage deeply with the content and discern the author's purpose and message. While looking at the title and first sentence can offer initial insights, it is the detailed analysis that truly uncovers the central theme. Background information about the author or other texts on the same subject may provide context, but they do not directly help in finding the central idea as effectively as a thorough examination of the text itself.